Optical disc storing both video titles provided with av function and video titles with no such functions which can instantly distinguish between such kinds of titles, and a reproduction apparatus and reproduction method for such disc

ABSTRACT

A multimedia optical disc on which a variety of types of video titles are recorded and which enables a reproduction apparatus to instantly distinguish whether emulated AV functions may be performed for any of the titles. The multimedia optical disc includes a manager area which stores playback type information corresponding to the management information for each video title, with the playback type information including a first flag showing whether the present video title is expressed using one or a plurality of sets of route information and a second flag showing whether a title is expressed using any branch information.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical disc onto which aninformation signal is recorded and to a reproduction apparatus for thedisc. In more detail, the present invention relates to an optical discused for recording multimedia data, such as digital video data, audiodata, and graphics data, and to a reproduction apparatus for suchoptical disc.

2. Description of the Related Art

The achievement of large-capacity optical discs in recent years has ledto a great deal of research into the development of multi-title opticaldiscs. Here, the expression “multi-title” refers to the storage of avariety of video titles on a single disc to improve thecost-effectiveness of distribution and retailing of video titles, and,by doing so, increase the value-added of optical discs.

The expression “video titles” is used here to loosely refer to any videoproduction which is represented by one or more sets of routeinformation, which show the reproduction routes to be taken by anoptical pickup when reading the optical disc, and sets of videoinformation that are successively read by the optical pickup whentracing one of the reproduction routes. The video information referredto here is multiplexed data (usually referred to as an MPEG stream)which is made up of video data and audio data that have been subjectedto compression at a high compression rate according to MPEG (MovingPictures Experts Group) techniques.

FIG. 1 shows the structure of video titles which are recorded onto amulti-title optical disc. In this drawing, the expression “Single PGC”indicates titles which each only use one set of route information, while“Multi PGC” indicates titles which each include a plurality of sets ofroute information. The label “Loop present” indicates the presence of aloop attribute in the route information, with this attribute indicatingthe repetition of the retrieval of image information, while “No loop”indicates that no such loop attribute is present. Similarly, the label“Branch present” indicates the presence of conditional branchinformation in the route information, this conditional branchinformation indicating a branch to another set of route informationwhich is performed interactively in response to a user operation.

In FIG. 1, the title for species (1) indicated by the labels “SinglePGC”, “No branch”, and “No loop” is a single sequential title. A singlesequential title refers to a title whose reproduction order is fixedaccording to one set of route information which has the title reproducedn order from the opening scene to the ending scene.

On the other hand, species (4), indicated by the labels “Multi PGC”, “Nobranch”, and “No loop”, is a multi-sequential title. Here, amulti-sequential title is a title which can be reproduced in a varietyof reproduction orders according to a plurality of sets of routeinformation, and so is not simply reproduced from start to end.

Species (2) and (3) indicated by the labels “Single PGC”, “No branch”,and “Loop present”, or “Multi PGC”, “No branch”, and “Loop present” arequiz-type titles. Quiz-type titles are video titles where the videoinformation indicated by the route information is read many times in arandom order. Examples of such quiz-type titles are aerobics titles andeducational titles which use drills.

Species (5) and (6) indicated by the labels “Multi PGC”, “Branchpresent”, and “Automatic”, or by the labels “Multi PGC”, “Branchpresent” and “Interactive” correspond to titles which are known as“interactive titles”. Here, interactive titles are titles whosereproduction route dynamically changes in accordance with useroperations made in response to menus that are displayed during thereproduction of the title.

The difference between interactive titles with the “Interactive” and“Automatic” labels is that “Automatic” interactive titles include adefault reproduction route which is prepared beforehand for the casewhen no user selection operation of a branch destination is made.

The difference kinds of title in species (1) to (6) are classifieddepending on the number of reproduction routes, the existence of branchinformation, and the existence of loop attributes. Here, information forclassifying the titles stored on an optical disc into these differenttypes is generally referred to as the “formation” of a title.

The big disadvantage of storing different species (1) to (6) of videotitles on a single optical disc is that a complex logical structure isrequired. Because of this complexity, it is difficult to achieve thereproduction features provided on conventional image reproductionapparatuses such as CD (Compact Disc), laser disc, or video CD players.Here, CD, laser disc, and video CD players are generally regarded ashousehold AV (Audio-visual) appliances, with a search function and afeedback function being examples of the functions provided by suchappliances which are problematic for multi-title discs.

The search function provided on a conventional AV appliance enablesusers to directly input a chapter number, song number, or expectedreproduction time which may be written on the case of the disc, and bydoing so instantly achieve reproduction of their desired data. Thefeedback function is a function which displays a chapter number, songnumber and/or present reproduction time to give the user real-timefeedback showing what part of the data is presently being reproduced,with the reproduction time and chapter number being constantly updatedas the reproduction of the disc progresses. These AV functions requirethe establishment of one-to-one correspondence between the disc storageaddress of a set of data and the chapter number, song number and/orpresent reproduction time of the set of data. For conventional CDs,video CDs, and laser discs, data is recorded sequentially on a spiraltrack, so that disc reproduction apparatuses have been able to know thepresent reproduction time and present chapter number by merely lookingat the disc storage address of the data presently being reproduced. As aresult, when a chapter number or reproduction time is directly inputtedby the user, such reproduction devices have been able to directly jumpto the data which corresponds to the user indication. In the followingexplanation, the case where a jump is performed to data indicated by theinput of a reproduction time (so many minutes and seconds) by the userwill be referred to as a “time search”, while the case when a jump isperformed to data corresponding to an inputted chapter number will bereferred to as a “chapter search”.

For a multi-title optical disc, there is no one-to-one correspondencebetween disc storage addresses of sets of data and chapternumbers/reproduction time. As a result, it is necessary for discreproduction apparatuses of multi-title optical discs to performemulated AV functions. Here, the expression “emulated AV functions”refers to the execution by multi-title disc reproduction apparatuses offunctions whose results resemble those of the search function andfeedback function of conventional disc players.

When a multi-title optical disc reproduction apparatus is instructed toreproduce a video title, the decision as to whether to perform emulatedAV functions for the indicated video title is made based on the numberof sets of route information, on the existence of branch information, onthe existence of loop attributes, and on the relation between the memorysize of the disc reproduction apparatus and the execution speed. Here,it is necessary for the disc reproduction apparatus to determine whetherthe title only includes one set of route information, whether loopinformation exists, whether automatic branches exist, and whetherinteractive branches exist. However, since loop information, automaticbranch information, and interactive branch information are distributedacross an optical disc, the determination of the presence of each ofthem takes a considerable amount of processing time.

The following is an explanation of an example operation when a userinserts a multi-title optical disc into the disc reproduction apparatusand indicates the reproduction of one of the titles on the disc. Here,in order to determine whether emulated AV functions can be performed forthe selected title, the disc reproduction apparatus has to determinewhether there is only one set of route information, whether loopinformation is present, whether any automatic branches are present, andwhether any interactive branches are present. Here, the apparatus canonly know whether loop attributes or branch information are included inthe sets of route information by referring to all sets of routeinformation used by the indicated title. Here, there is the possibilitythat even if a first set of route information does not include routeinformation, a second or third set of route information may stillinclude branch information, so that the reproduction apparatus must goto the trouble of referring to all of such sets of route information,thereby consuming a considerable amount of processing time.

The above example corresponds to a title classifying method (used by thepresent video CD standard) wherein branch information can be provided insets of route information, although in interactive software developed inrecent years, there is an increasing tendency for the provision of farmore complex changes in image reproduction by providing routeinformation which contains reproduction control information forperforming branches and a variety of other forms of reproductioncontrol.

Aside from the provision of reproduction control information in sets ofroute information, it is also possible to provide the same kind ofreproduction control information in the management informationinterleaved into MPEG streams, or to distribute reproduction controlinformation between MPEG management information and sets of routeinformation, so that a great variety of story developments can beachieved. As a result, it becomes extremely difficult to detectreproduction control information which is distributed between so manylocations to judge whether emulated AV functions are possible. Moreover,the reproduction of video data is performed for units which are severalmegabytes long, so that the investigation of reproduction controlinformation is included in this kind of MPEG stream requires a memorycapacity and disc seek speed which are well beyond the capability ofeconomically-viable disc reproduction apparatuses.

In view of the difficulties when a plurality of titles are to be storedon a single optical disc, it has been suggested that AV functions shouldnot be provided for any of the titles on a multi-title disc. However, insuch a case, when viewing a same kind of title as was available forconventional video CD or laser disc, the user will not be able to makeuse of the AV functions to which he/she has become accustomed, therebypreventing jumps to a specified chapter number or reproduction time.This will not meet the user expectations for such reproduction and canbe potentially lead to user dissatisfaction with this kind of equipment.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a multimediaoptical disc and disc reproduction apparatus which can instantlydistinguish whether emulated AV functions are possible for a title, evenwhen video titles of a variety of types are recorded on a same opticaldisc. In more detail, the primary object of the present invention is toprovide a multimedia optical disc and disc reproduction apparatus which,even if there are great discrepancies in the number of sets of routeinformation used by titles, and if there is the possibility that branchinformation for branches to different sets of route information arepresent in both the variable code-length data (such as video data ofseveral megabytes in length) and the route information, can stillinstantly distinguish whether emulated AV functions are possible for atitle.

In order to achieve the stated object, the multimedia optical disc ofthe present invention is an optical disc which includes a title area anda manager area. The title area stores a plurality of video titles whichare video productions that are expressed using route information showinga route to be taken by an optical pickup and a plurality of sets ofvideo information which are read in accordance with the routeinformation. The manager area stores information for managing the videotitles stored in the title area. Here, the titles stored in the titlearea include a first type which are expressed using one set of routeinformation, a second type expressed using a plurality of sets of routeinformation and branch information for establishing interactive branchcontrol, and a third type expressed using a plurality of sets of routeinformation but no branch information.

The manager area is characterized by including an address managementarea for storing management information for managing the address of eachvideo title, and a reproduction type information area for storingreproduction type information which includes a first flag correspondingto the management information for each video title which shows whetherthe title is expressed by a single set of reproduction information or aplurality of sets of reproduction information and a second flag whichshows whether the title is expressed using any branch information.

With the stated construction, reproduction apparatuses can instantlyknow whether each title includes branch information which may be presentin management information which can be in any set of route informationor management information that is interleaved into image informationwhich can be tens of megabytes in size.

As a result, even when a user attempts to perform a chapter search ortime search immediately after loading an optical disc into areproduction apparatus, the reproduction apparatus can immediatelydetermine whether such chapter search and time functions should beenacted or prohibited.

With the present disc, it is possible to record titles which contain agreat variety of possible story developments due to the existence ofbranch information in both the management information and the routeinformation on a same disc as orthodox titles for which emulated AVfunctions can be performed during reproduction. Chapter number displayand reproduction elapsed time display are only performed for appropriatetitles, with the reproduction apparatus prohibiting display when notappropriate. In this way, the system ensures that inappropriate chapteror reproduction time display is not performed.

The reproduction apparatus for the present multimedia optical disc maycomprise an optical pickup for optically reading data stored on themultimedia optical disc, a drive mechanism for the optical disc, a firstcontrol means for controlling the drive mechanism to read the recordedcontent of the manager area, a manager buffer for storing the contentread from the manager area, a first receiving means for receiving anindication of a selection of an image title to be reproduced from theuser, a calculation means for referring to the manager buffer andcalculating an address of the title received by the first receivingmeans, a second control means for controlling the drive mechanism toread the video title from the address calculated by the calculationmeans, a judging means for referring to the first and second flags inthe reproduction type information corresponding to the selected titleand judging whether execution of AV functioning is possible for theselected title, and an AV function executing means for executing AVfunctions when judged possible, the AV functions at least including asearch function for searching to an arbitrary position in a title basedon an appropriate indication and a feedback function for monitoring anddisplaying a reproduction elapsed time. With this construction, thereproduction apparatus can instantly know whether each title includesbranch information which may be present in management information whichcan be in any set of route information or management information that isinterleaved into image information which can be tens of megabytes insize.

As a result, even when a user attempts to perform a chapter search ortime search immediately after loading an optical disc into areproduction apparatus to view a desired scene, the reproductionapparatus can immediately determine whether such chapter search and timefunctions should be enacted or prohibited.

The present reproduction is also able to reproduce titles which containa great variety of possible story developments due to the existence ofbranch information in both the management information and the routeinformation in addition to orthodox titles for which emulated AVfunctions can be performed during reproduction.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention willbecome apparent from the following description taken in conjunction withthe accompanying drawings which illustrate a specific embodiment of theinvention. In the drawings:

FIG. 1 shows examples of the kinds of titles that are stored on amulti-title disc;

FIG. 2A shows the appearance of the optical disc used in the presentembodiment;

FIG. 2B shows a cross-section of the optical disc;

FIG. 2C shows an enlargement of the area around the focused spot of thelaser beam;

FIG. 2D shows sequences of pits in the information layer 109;

FIG. 3A shows the track arrangement of the information layer of theoptical disc;

FIG. 3B shows the physical sectors of the information layer of theoptical disc;

FIG. 4A shows the logical construction of the optical disc;

FIG. 4B shows the basic arrangement of the file layer and theapplication layer;

FIG. 5A shows an example of a group of video materials which belong toVideo Title Set V1;

FIG. 5B shows the internal composition of the VOBs which are included inthe group of video materials of Video Title Set V1;

FIG. 6 shows the correspondence between the video materials, audiomaterials, and subtitle materials and each pack in a video object (VOB);

FIG. 7 shows the internal composition of a management information pack;

FIG. 8 shows the internal composition of a set of VTS managementinformation;

FIG. 9 shows an example of the internal composition of the VTS internaltitle search pointer table;

FIG. 10A shows the internal composition of the PGC informationmanagement information table in a set of VTS management information;

FIG. 10B shows the format of the PGC information;

FIG. 10C shows the internal composition of the VOB position informationtable;

FIG. 11 shows an example of the internal composition of the VideoManager;

FIG. 12 shows an example of a volume menu;

FIG. 13 shows an example of the internal composition of the Highlightinformation for a volume menu;

FIG. 14 shows an example of the internal composition of the VM internaltitle search pointer table;

FIG. 15 shows a perspective view of the reproduction device of thepresent embodiment;

FIG. 16 shows an example of the key arrangement of the remote controller91;

FIG. 17 is a block diagram of the internal construction of the DVDplayer 1 of the present invention;

FIG. 18 is a block diagram showing the composition of the signalseparating unit 86;

FIG. 19 shows the internal construction of the system control unit 93;

FIG. 20 shows an example of the permitted function table 763;

FIGS. 21A to 21D are flowcharts for the processing of the system controlunit 93;

FIGS. 22A to 22D are flowcharts for the processing of the remotecontroller processing routine of the system control unit 93; and

FIG. 23 shows another example of the flag composition of the titleplayback types.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to assist the reader's understanding, the following explanationhas been divided into items which have each been given an index number.Here, the number of digits in the index number indicates the level ofthe item in question in the overall structure of the explanation. Here,the highest-ranked classification numbers are (1) and (2), with (1)relating to the optical disc and (2) relating to the reproduction device(disc player).

-   -   (1) Physical Construction of the Optical Disc    -   (1.1) Logical Construction of the Optical Disc    -   (1.1.1) Logical Construction . . . Video Title Set    -   (1.1.1.1) Video Title Set . . . Video Object (VOB)    -   (1.1.1.1.1) Video Object (VOB) . . . Management Information Pack    -   (1.1.1.2) Video Title Set . . . -Video Title Set Management        Information    -   (1.1.1.2.1) Video Title Set Management Information -PGC        information    -   (1.1.2) Logical Construction-Video Manager    -   (2.1) Outline of the Disc Reproduction Device    -   (2.2) Construction Elements of the Disc Reproduction Device    -   (2.2.1) Disc Reproduction Device . . .

Construction of Signal Separating Unit 86

-   -   (2.2.2) Disc Reproduction Device . . . Construction of System        Control Unit 93        (1) Physical Construction of the Optical Disc

A digital video disc (DVD) which has a diameter of 120 mm and has astorage capacity of 4.7 GB on one side is ideally suited for use as themultimedia optical disc of the present embodiment.

FIG. 2A shows the appearance of the optical disc, while FIG. 2B showsits cross-section, and FIG. 2C shows an enlargement of the circled partof FIG. 2B. Starting from the bottom of this figure, DVD 107 is formedof a first transparent substrate 108, an information layer 109, abonding layer 110, a second transparent substrate 111 and a print layer112 for printing a label.

The first transparent substrate 108 and the second transparent substrate111 are reinforcing substrates which are made of a same material and arearound 0.6 mm thick. This is to say, both substrates are roughly 0.5mm-0.7 mm thick.

The bonding layer 110 is provided between the information layer 109 andthe second transparent substrate 111 to bond them together.

The information layer 109 includes a reflective membrane, such as metalfoil, which is attached to the first transparent substrate 108. Here, ahigh density of indented and protruding pits is formed in thisreflective membrane by a manufacturing process.

The shape of these pits is shown in FIG. 2D. As shown in FIG. 2D, thelength of the pits varies between 0.4 μm and 2.13 μm, with the pitsbeing aligned in a spiral with radial intervals of 0.74 μm between themto form one spiral track.

By shining the laser beam 113 on these pits and measuring the changes inthe reflection ratio of the light spot 114 shown in FIG. 2C, informationcan be retrieved from the disc.

The light spot 114 on a DVD has a diameter of around 1/1.6 times thediameter of a light spot on a conventional CD due to an increase in thenumerical aperture (NA) of the objective lens and a reduction in thewavelength λ of the laser beam.

DVDS of the physical construction described above can store around 4.7GB of information on one side, which is almost eight times the storagecapacity of a conventional CD. As a result, it is possible to achieve agreat improvement in picture quality for moving pictures and to increasethe reproduction time from the 74 minutes which is possible with a videoCD to over two hours.

The substrate technique which has enabled this improvement in storagecapacity is a reduction of the spot diameter D of the laser beam. Here,spot diameter D is given by the equation “D=laser wavelength λ/numericalaperture of objective lens NA”, so that the spot diameter D can bereduced by reducing the laser wavelength λ and by increasing thenumerical aperture of objective lens NA. It should be noted here that ifthe numerical aperture of objective lens NA is increased, comaticaberration occurs due to the relative inclination, known as “tilt”,between the optical axis of the beam and the disc surface. In order tosuppress this phenomenon, DVDs use a transparent substrate of reducedthickness. Such a reduction in the thickness of the transparentsubstrate creates the problem of reduced physical durability for thedisc, although this problem can be overcome by reinforcing DVDs withanother substrate.

Data is read from DVDs using an optical system with a short wavelength(650 nm) red semiconductor laser and an objective lens whose NA(numerical aperture) can be enlarged up to around 0.6 mm. If thethickness of the transparent substrate is reduced to around 0.6 mm, astorage capacity of up to 4.7 GB can be achieved for one side of a 120mm diameter optical disc.

FIG. 3A shows the arrangement when the spiral track is formed leadingfrom the inner periphery to the outer periphery of the information layer109, with a very large number of physical sectors being formed on thisspiral track. In the present embodiments, a physical sector is an curvedarea on the spiral track, and is the smallest unit of data which can bereliably retrieved.

Each sector has the internal construction shown in FIG. 3B to ensure thereliability of data retrieval. As shown in FIG. 3B, each sector is madeup of a sector header area which is used to identify the respectivesector, a user data area for storing 2 Kbytes of data, and an errorcorrection code storage area which stores an error correction code forthe user data area in the same sector. When reading the user data areain the same sector, a disc reproduction device uses the error correctioncode to detect any errors in the sector, and performs error correctionwhen such errors are detected.

(1.1) Construction of the Optical Disc

The following is an explanation of the logical construction of theoptical disc. This logical construction is made up of a three-levelhierarchy. The hierarchy is made up of a lowest level whose logicalconstruction is oriented towards the firmware of the disc reproductionapparatus, a file level whose logical construction is oriented towardsthe operating system of a personal computer or workstation, and anapplication level which has a multi-title logical construction. Here,the logical construction of the lowest level is shown in FIG. 4A and thelogical constructions of the file level and the application level areshown in FIG. 4B.

The following explanation will first deal with the lowest level whoselogical construction is oriented towards firmware. Here, firmware refersto the control program for controlling a mechanical construction whichincludes a spindle motor and an actuator for an optical pick-up. Inorder from the top of FIG. 4A, the logical format of the lowest level iscomposed of a lead-in area which has identification information includedin a sector address, a volume area and finally a lead-out area, so thaton reading such, the firmware has the spindle motor and actuator of theoptical pickup activated.

The lead-in area stores operation stabilization data and the like whichis used when the disc reproduction apparatus starts reading data fromthe optical disc. The lead-out area informs the reproduction device ofthe end of reproduction and does not store meaningful data.

The volume area is an area for storing many kinds of data, as well asfor managing the physical sectors to which the volume area belongs aslogical blocks. These logical blocks are identified by firmware usingserial numbers which are assigned to consecutive physical sectors, withthe first physical sector in the data recording area being assigned thenumber zero. The enlarged portion “b301” of FIG. 3A shows a group oflogical blocks in the volume area. Here, the figures, #m, #m+1, #m+2 and#m+3 which are appended to the logical blocks in this circled area arethe logical block numbers.

The following is an explanation of the file level and the applicationlevel. This file level and application level exist in the volume areashown in FIG. 4A.

The file level is divided into a volume management area and a file area.The volume management area stores file system management informationwhich is used to manage a plurality of logical blocks as files, inaccordance with IS013346 Standard. The file system managementinformation shows the relations between the file names for a pluralityof files and addresses of the groups of logical blocks which contain thecorresponding files. This file system management information is used bythe disc reproduction device to access the disc in file units. Morespecifically, on being given a file name by an application program, theoperating system of a personal computer or workstation refers to all thesystem management information to calculate all of the groups of logicalblocks for the file, before accessing these groups of logical blocks tofetch the desired digital data.

The following is an explanation of the logical construction of theapplication level. The information in this application level can be mostloosely classified into a Video Manager and a plurality of Video TitleSets. Here, a Video Title Set is a group of movie titles which areclassified from the viewpoint of common use of a same set of videomaterial, while the Video Manager is information for managing all of thegroups in the title sets as a single set. In the example shown in FIG.4B, the grouping of video materials included in Video Title Set V1 is acollection of action scenes used in an action movie, while the groupingof video materials included in Video Title Set V2 is a collection ofimages shot on location at historical sites around the world.

Using the video materials included in Video Title Set V1, the titledeveloper can produce a disc whereby a user may enjoy a no-cut versionof action movie A, a general cinema release of action movie A, atelevision broadcast version of action movie A, an interactive versionof action movie A, or a picture profile of the cast of action movie A.By making good use of common video materials on a single disc in thisway, the developer can provide a plurality of applications to the user.

Using the video materials included in Video Title Set V2, the titledeveloper can produce a disc whereby a user may enjoy a documentaryabout the excavation of historical sites, a multimedia guide tohistorical sites, an adventure game where participants search forhistorical sites, or a quiz about historical sites around the world. Bymaking good use of common video materials on a single disc in this way,the developer can provide a plurality of applications to the user.

By classifying video titles in this way, it is possible to have aplurality of titles with common video materials grouped together.

(1.1.1) Logical Construction of Video Title Set

A Video Title Set consists of a set of Video Title Set managementinformation and a group of video materials. The following explanationwill first deal with the group of video materials in the Video TitleSet. Normally, when a movie is recorded onto film or video tape, anediting process is performed whereby only the required scenes are cutfrom the master tape after filming and are arranged into the order ofthe story, but when such scenes are recorded into a Video Title Set,such editing operations are not performed. This is to say, there are notraces of an editing process in which only the necessary parts of thenecessary scenes are extracted and arranged into the order of the story.In fact, a Video Title Set can store video materials in a completelyrandom order without any extraction of necessary materials from theoriginal footage. The group of video materials which are stored in VideoTitle Set V1 are shown in FIG. 5A. While the scenes in FIG. 5A may beconstrued as forming the order of a story, this is merely for the sakeof explanation, and in no way represents a necessary condition for thestorage of a group of video materials.

The Video Title Set V1 in FIG. 5A includes a plurality of video objects(VOBs) which each have different reproduction times. Here, theexpression “VOB” refers to one set of multiplexed stream data that ismade up of various kinds of stream data, such as video data, audio data,sub-picture data, and control data, which are of variable code length,or in other words, an MPEG stream which is the unit used for one sceneon a DVD. In the figure, VOB#1 has a reproduction time of ten minutes,and is an opening scene with scrolling credits showing the names of thedirector, the producer, the studio, and the cast. As another example,VOB#2 has a reproduction time of fifty seconds and is a scene whichshows the main character walking around the Doutomburi area of OsakaCity This scene is actual footage shot using famous actors on location.

FIG. 5B shows how the sets of stream data of variable code length aremultiplexed into one VOB. Here, each VOB is composed of a plurality ofVOB units which are arranged in a time series starting from the firstVOB unit. Each VOB unit which forms part of a VOB is a set ofmultiplexed data with a reproduction time which is usually 0.5-1.0seconds. Here also, the variable code length data which can bemultiplexed into a VOB is made up of video data, audio data, andsub-picture data, with the sets of these kinds of data which aremultiplexed into each VOB unit being called video packs, audio packs,and sub-picture packs, each being 2 K bytes in size.

In the example shown in FIG. 5B, VOB#1, whose reproduction time is tenminutes, is made up of 1,200 (=10*60*2) VOB units, while VOB#2, whosereproduction time is fifty seconds, is made up of 100 (=50*2) VOB units.In the same way, VOB#3, whose reproduction time is eight minutes, ismade up of 900 (=8*60*2) VOB units, while VOB#4, whose reproduction timeis forty-eight seconds, is made up of 96 (=48*2) VOB units.

While the VOB units in each VOB are arranged into a time series, eachpack in each VOB unit is arranged in an order which, with the exceptionof the provision of the pack management information at the front, iscompletely random in terms of number of packs and pack order. This is tosay, there can be VOB units which have the order audio data, sub-picturedata, video data, and other VOB units which have the order, sub-picturedata, video data, audio data. As other examples, there may also be VOBunits which are made up of three hundred or so packs of nothing butvideo data, and other VOB unit which are made up of five hundred or sopacks.

Here, the reason the order of the packs can be different for each VOBunit is that it is not necessary for packs of a same kind to be next toeach other when the variable code length data is fetched and buffered bya reproduction apparatus. The example shown in FIG. 5B has the packsarranged into a regular order in each VOB unit, although this is merelyfor the sake of explanation and is not a necessary condition for thedata construction.

The reason why there is a variable number of video and sub-picture packsis that these kinds of data are coded with a variable code length, sothat even if both kinds of pack have a reproduction time of 0.5-10seconds, there is a considerable difference in the amount of data whichis required to achieved such reproduction. The most clear example isdata for a moving image. When reproducing a background still image for0.5 seconds, or a static close-up of a character's facial expression for0.5 seconds, only a small amount of data is necessary. However, toreproduce a moving image of an actor whose movements are pronounced, amuch larger amount of data is required. This large discrepancy in theamount of data is due to the fact that the reproduction of a staticimage, such as the background image or the character's expression, canbe achieved using only one frame which is subjected to frame internaldecoding and field internal decoding, while action scenes and car chasescenes need to utilize movement compensation prediction to compensatefor the movement of the object being filmed.

Large discrepancies are also present for sub-picture data, so that thereare large differences in the amount of subtitle information betweenscenes where the characters are engaged in a lively argument, and sceneswhere the characters are calmly shaking hands, which in turn leads todifferences in the number of sub-picture packs provided in each VOB unitfor a reproduction time of 0.5 seconds.

To achieve reproduction with the unit time at 0.5 seconds, it isnecessary to inform the disc reproduction apparatus before the start ofthe 0.5 second period where it is sufficient to transfer only a smallamount of data, or whether a large amount of data is required, and tohave the decoder provided in the disc reproduction apparatus performdecoding for the necessary amount of transferred data. Here, to havevariable code-length data reproduced with a uniform reproduction time of0.5 seconds, a management information pack is provided at the start ofeach set of VOB unit, with this management information pack indicatingtransfer rate which is required for the reproduction of the VOB unit towhich it belongs, as well as the transfer rate and buffer size which arerequired by each of the video stream, the audio stream, and themanagement information stream in the VOB unit. By having the managementinformation pack specify the transfer rates in this way, the discreproduction apparatus is able to decode the video data, audio data, andsub-picture data which follows the management information pack. To givea specific numerical example, 0.5 seconds of video reproduction willgenerally require several hundred video packs, with the reproductiondevice being informed of a necessary transfer rate in the region of 4.5Mbit/second before such number of packs are read from the DVD to enablethe decoding of such number of video packs.

For the example shown in FIG. 5B, if each VOB unit is considered ascomprising an average of 200 packs, VOB#1, which has a reproduction timeof ten minutes and is made up of 1,200 (=10*60*2) VOB units, will bemade up of 240,000 packs. Of these, 1,200 will be management informationpacks. Since the size of each pack is standardized at 2 Kbytes, thestorage of this VOB#1 will take up a 480 Mbyte (=240,000*2 Kbyte) areaon a DVD.

In the same way, VOB#3, which has a reproduction time of eight minutesand which is made up of 960 (=8*60*2) VOB units, will be made up of192,000 packs, so that the storage of VOB#3 on a DVD will take up a 384Mbyte (=192,000*2 Kbyte) area.

VOB#4, which has a reproduction time of forty-eight seconds and which ismade up of 96 (=48*2) VOB units, will be made up of 19,200 packs, sothat the storage of VOB#3 on a DVD will take up a 38.4 Mbyte (=19,200*2Kbyte) area.

The video packs stored in a video object (VOB) are arranged so that thedigital data in the video packs in one VOB unit forms at least one setof digital video data called a group of pictures (GOP). Here, theexpression “group of pictures” refers to the unit which is used whendecompressing compressed digital video data, and is made of aroundtwelve to fifteen frames of video data. The details of GOPs arestandardized according to the MPEG2 (Moving Pictures Experts Group)standards, ISO 11172 and ISO 13818.

FIG. 6 shows the relation between each pack in a video object (VOB) anda video scene. In the figure, the video material in this one scene isdepicted using a long horizontal strip which has been positioned abovethe VOB. Three channels of audio materials and two channels of subtitlematerials are also given below the VOB. In FIG. 6, the arrows shownextending downwards from the video materials show how the videomaterials are stored in each video pack provided in the data field ofthe VOB.

By tracing the arrows from the video materials, it can be seen that thevideo from the start of reproduction of the scene to the 0.5 second markis coded into I pictures (Intra-pictures), P pictures (Predicativepictures), and B (Bidirectionally predicative pictures) and then storedin the data fields of video packs 1 and 2 in VOB unit 1. As describedabove, the video data will in reality be stored in several hundred videopacks, though, for ease of explanation, only two of such packs have beenshown in FIG. 6. In the same way, the video from the 0.5 second mark tothe 1.0 second mark is coded in I pictures, P pictures, and B picturesand is then stored in the data fields of video packs 3 and 4 in VOB unit2. Although not shown in the drawing, the video from the 1.0 second markto the 1.5 second mark is coded and stored in the data fields of thevideo packs in the next VOB unit.

The following is an explanation of the relation between the threechannels of dubbing soundtracks for one scene and the audio packs in thedata field of the VOB. In the same way as with the video data, thearrows extending away from the audio materials to the audio packs in theVOB show that the audio materials are subjected to one of two kinds ofcoding and are stored in the data field of each audio pack in 0.5 secondunits. This is to say, the dubbing soundtrack on channel A from thestart of the reproduction of the scene to the 0.5 second mark isrecorded in the data field of audio pack A-1 of VOB unit 1, while thedubbing soundtrack on the same channel from the 0.5 second mark to the1.0 second mark is stored in the data field of audio pack A-2 in VOBunit 2. Although not shown in the drawing, the audio on this channelfrom the 1.0 second mark to the 1.5 second mark is coded and stored inthe data field of the audio pack A-3 in the next VOB unit. As describedabove, synchronization between audio and video is achieved using a PTS(Presentation Time Stamp) which is standardized under MPEG, so that itis not necessary for all of the audio data to be included in the sameVOB units as the video data to which it corresponds, so that such audiodata may in fact be stored in a preceding or succeeding VOB unit, forexample.

The dubbing soundtrack on channel B from the start of the reproductionof the scene to the 0.5 second mark is recorded in the data field ofaudio pack B-1 of VOB unit 1, while the dubbing soundtrack on the samechannel from the 0.5 second mark to the 1.0 second mark is stored in thedata field of audio pack B-2 in VOB unit 2. Although not shown in thedrawing, the audio on this channel from the 1.0 second mark to the 1.5second mark is coded and stored in the data field of the audio pack B-3in the next VOB unit.

The dubbing soundtrack on channel C from the start of the reproductionof the scene to the 0.5 second mark is recorded in the data field ofaudio pack C-1 of VOB unit 1, while the dubbing soundtrack on the samechannel from the 0.5 second mark to the 1.0 second mark is stored in thedata field of audio pack C-2 in VOB unit 2. Although not shown in thedrawing, the audio on this channel from the 1.0 second mark to the 1.5second mark is coded and stored in the data field of the audio pack C-3in the next VOB unit.

The audio data on the three channels which are distributed among thedata fields of audio pack A-C will hereinafter be referred to as audiodata A, audio data B, and audio data C. As one example, a dubbingsoundtrack in English can be set as audio data A, a dubbing soundtrackin French can be set as audio data B, and a dubbing soundtrack inJapanese can be set as audio data C, so that the user can switch betweenthem as desired.

In the example shown in FIG. 6, two sub-picture packs A, B are presentin each VOB, so that two channels of subtitles can be stored distributedbetween the data fields of sub-pictures A, B in each VOB unit. As oneexample, English subtitles can be displayed as sub-picture data A, withFrench subtitles being displayed as sub-picture data B, so that the userwill be able to switch between them.

By sorting the pack data according to type and recombining, digital datasequences which are formed of video data, audio data, sub-picture data,or control data are produced. These sorted and recombined groups of packdata are called elementary streams, so that each VOB is a programstream, or “system stream” which is made up of a plurality of theseelementary streams.

(1.1.1.1) Video Object (VOB)—Management Information Pack

Management information packs have been described above as specifying atransfer rate and as being arranged at the front of each VOB unit. Sincea management information pack is stored at the front of each VOB unit,each management information pack is only opened in a buffer in the discreproduction apparatus for the 0.5 seconds while the video packs, audiopacks, and sub-picture packs in the first VOB unit are read andreproduced, before the management information pack in the next VOB unitis read. Once this 0.5 period has expired, the next managementinformation pack is overwritten into the buffer. Since each managementinformation pack is only opened in the buffer during the reading of thevideo, audio, and sub-picture packs in the same VOB unit, in addition tothe transfer rate, control information which only applies to the presentVOB unit can be indicated to the disc reproduction apparatus for onlythe 0.5-1.0 second period for which the video, audio, and sub-picturepacks in the present VOB unit are reproduced.

FIG. 7 shows the data construction of the management information pack.While the video packs, audio packs, and sub-picture packs are eachformed of one packet, the management information packs are each formedof two packets. Of these, one packet is called a PCI packet(Presentation Control Information packet) and the other is called a DSIpacket (Data Search Information packet). The data construction of amanagement information pack is somewhat different to that of a videopacket or an audio packet in that it is made up of a “pack header”, a“system header”, a “packet header for PCI packet”, a “data field for PCIpacket”, a “packet header for DSI packet” and a “data field for DSIpacket”.

The system header stores management information for the entire VOB unitwhich has this management information pack at the front, according toMPEG standards. It stores the overall necessary transfer rate and anindication of a transfer rate and buffer size for each of the videostream, the audio stream, and the sub-picture stream.

The stream IDs of the two packet headers in a management informationpack, as shown by the oblique shading in FIG. 7, is set at theidentification code “1011 1111” which indicates “private stream 2”.

The PCI packet contains the Highlight information which is used toperform reproduction control in accordance with cursor operations formenus and confirmation operations for items, when the sub-picture packis used to display a menu made up of a plurality of items. In thepresent embodiment, branches of reproduction route which perform aswitch from a present reproduction route to another reproduction routeare a representative example of such “reproduction control in accordancewith confirmation operations”. Here, switching of reproduction route isperformed by having commands, named “Highlight commands”, stored in theHighlight information corresponding to each item in a menu, and byhaving these commands executed when the management information pack isread by the disc reproduction apparatus. Since these commands whichcorrespond to each item, which in turn correspond to the confirmationoperation, are executed selectively, reproduction routes can be switchedin units of one set of PGC information. PGC information is described inmore detail later in this specification.

A DSI packet stores information which is necessary for the reproductionof an MPEG stream from the present data position. Each DSI packet alsostores the addresses of the preceding and succeeding DSI packets, whichare referred to when special reproduction functions, such as fastforward, are performed.

This concludes the explanation of video objects (VOB), so that thefollowing explanation will deal with the composition of the Video TitleSet management information in the Video Title Set.

(1.1.1.2) Video Title Set—Video Title Set Management Information

The Video Title Set management information is a collection of controlinformation for reproducing the video materials, which have not beensubjected to any editing processes and have not been arranged in orderof reproduction, so that they make up one video title.

In the present embodiment, a video title is an image production that isexpressed using (1) a Video Title Set number which is uniquely assignedto the title on the optical disc, (2) one or more sets of PGCinformation which show the route taken by the optical pickup in readingthe optical disc, and (3) image information which is successively readfrom the optical disc in accordance with the PGC information. Thesekinds of information are managed by the title set management informationfor each Video Title Set. An example of such Video Title Set managementinformation is shown in FIG. 8. As shown in FIG. 8, this Video Title Setmanagement information is composed of a VTS internal title searchpointer table, a PGC management information table, and a VTS time maptable.

The PGC management information table is a table which stores a pluralityof sets of PGC information. As described above, VOBs are not subjectedto editing processes, so that information showing which video materialsare to be extracted and reproduced in the required order is necessary.This role is fulfilled by the plurality of sets of PGC information inthe PGC management information table. Here, each set of PGC informationis information which, in addition to specifying the retrieval order ofVOBs, specifies the various control procedures to be executed by thedisc reproduction apparatus when the VOBs in question are reproduced.Examples of such control procedures are control to find a VOB (which isto be read according to PGC information) at the start of a chapterindicated by a chapter number, control to display the presentreproduction time for the VOB (which is to be read in accordance withPGC information), control to find a desired image content in accordancewith an indication of reproduction time, and control for performing abranch between sets of PGC information.

The order of VOBs in the sets of PGC information in the PGC managementinformation table is expressed as a sequence of sets of VOB positioninformation. Here, the order of position information held by sets of PGCinformation is interpreted by the disc reproduction apparatus as theretrieval order for VOBs. The sets of PGC information shown in thefigure each have a different retrieval order for VOBs, with this showingthat a plurality of video titles with different reproduction orders areachieved by having a plurality of sets of PGC information which eachhave rearranged position information for VOBs.

It should be especially noted here that there are branches between thesets of PGC information recorded in the PGC management informationtable. Here, many sets of PGC information which do not include definiteinformation showing where branches to the present set of PGC informationoriginate, or information showing what set of PGC information isbranched to next are recorded in the Video Title Set, since these setsof PGC information feature dynamic branches where conditional branchinstructions are performed in accordance with user operations madeduring reproduction.

The VTS (Video Title Set) internal title search pointer table is a tablewhich is made up of title numbers, and pointers to sets of PGCinformation which correspond to VTS title search pointer #1, VTS titlesearch pointer #2, VTS title search pointer #3 . . . and is a table usedfor referencing the sets of PGC information stored in the PGC managementinformation table using a VTS internal title number. Here, a VTSinternal title number is a locale number for managing separate titles inthe Video Title Set.

FIG. 9 shows an example of the content of the VTS internal title searchpointer table. As shown in this figure, the VTS internal title searchpointers #1, #2, and #3 are respectively made up of a Video Title Setnumber and VTS internal title number (this pairing corresponding to thetitle number assigned to one of titles), and a number (PGC number) of aset of linked PGC information.

The sets of PGC information which are linked to the VTS internal titlenumbers in VTS internal title search pointers #1, #2, and #3, are setsof PGC information which are specified by a selection operation made bythe user. These sets of PGC information are somewhat exceptional whencompared to other PGCs, which are stored without information showing theorigins of branches, in that they are specified by a clear operationmade by the user after referring to the available title names. As aresult, these sets of PGC information are appended with the label“Entry-PGC” to distinguish them from other sets of PGC information.

In the VTS internal title search pointer of the present embodiment,there are the differences described below for sets of entry-PGCinformation which correspond to title numbers.

In the present embodiment, titles recorded on an optical disc are madeup of titles which the developer has had recorded in a sequential orderfrom the opening scene to the ending scene (called “sequential titles”,see species (1) in FIG. 1), multi-story titles which dynamically changein accordance with the user operations which are performed duringreproduction (see species (6) in FIG. 1), and quiz-style titles wherethe same scenes can be shown several times or rearranged into randomorder (see species (2) in FIG. 1).

The Entry-PGC information for a sequential title, of which is PGCinformation #1 is an example, indicates all of the VOBs from the openingscene to the ending scene. This is to say, the linked construction ofVOBs is sequential. The VOB position information in such a set ofEntry-PGC information contains all of the scenes, so that the VOB usedin the reproduction of a play, for example, can be indexed with chapternumbers (Act numbers), which allows the user during reproduction tospecify a desired scene using such chapter numbers. Since the order ofVOBs from the opening scene to the ending scene is decided, it ispossible by counting the sets of VOB position information using theEntry-PGC information to have a reproduction present time displayedalong with a present chapter number on a panel provided on the discreproduction apparatus.

The Entry-PGC information for a multi-story title (such as PGCinformation #5) only indicates the VOB for the opening scene, so thatonce the opening scene has been reproduced, the disc reproductionapparatus executes a conditional branch. This conditional branch is aninstruction which indicates a switch to a branch destination set of PGCinformation in accordance with a user operation made duringreproduction. By having the disc reproduction apparatus perform thiskind of branch, a dynamic switch to a next scene is performed followingthe reproduction of the first scene.

Multi-story titles are interactive titles for which emulated AVfunctions are prohibited. This is because interactive titles are titleswhich are reproduced in accordance with user selections made usingmenus, so that it is necessary for all of the scenes which are notindicated by a user operation to be concealed. It is also technicallydifficult to assign consecutive numbers to the image data which is readfor interactive titles. Here, if a producer attempts to establish acorrespondence relationship, the correspondence between chapter numbersand scenes, and between the reproduction time and scenes will becomejumbled up, which will only confuse the viewer.

The Entry-PGC information in a quiz-type title (such as PGCinformation#3), indicates all of the VOBs from the opening scene to theending scene in the same way as with a sequential title, although theEntry-PGC information further contains an indication that the imagescenes will be selected and reproduced in a random order, so that theorder of VOBs indicated by this set of PGC information is kept secretfrom the user. In order to prevent the user from finding out this theimage content and order of image scenes by activating a chapter searchor time search, the activation of emulated AV functions is prohibited.

In FIG. 8, “VTS time search map #1-#12” is information which shows byhow many seconds the reproduction time display is updated when theoptical pickup is advanced by a given amount during a scanning of theoptical disc by the optical pickup based on any of the sets of PGCinformation. Accordingly, the time search map is composed of a group oftime updating points which will be passed by the optical pickup whenscanning the optical disc. This group of time updating points is a groupof addresses which are at intervals on the optical disc that correspondto time resolution. Here, time resolution refers to the notch widthwhich is used for reproduction time display, so that if, for example,this is one second, the time search map is composed so that timeupdating points are arranged at intervals of two VOBU. If this notchwidth is three seconds, the time search map is composed so that timeupdating points are arranged at intervals of six VOBU, since each VOBUcorresponds to a reproduction time of around 0-5 seconds. Here, VTS timesearch maps #1-#12 shown in FIG. 8 are all composed for PGC information#1, since out of the sets of PGC information #1-#6 in FIG. 9, a feedbackfunction is only possible for PGC information #1 that is set as theEntry-PGC of the sequential title.

(1.1.1.2.1) Video Title Set Management Information—PGC Information

The following is an explanation of the data construction and thedetailed content of the PGC information #1, #2, #3 . . . #6 in the PGCmanagement information table. Here, FIG. 10A shows an example of the PGCinformation management table. As shown in this figure, PGC information#1, #2, #3 . . . #6 have a common aspect in that they are all generatedwith the data format shown in FIG. 10B as a template, although they eachdiffer in content.

The VOB position information table uses sequences of VOB positioninformation to indicate to the disc reproduction apparatus what VOBsshould be read in what order for the present set of PGC information.Each set of VOB position information shows to the disc reproductionapparatus the storage position of each VOB on the optical disc, so thatthe disc reproduction apparatus can have the optical pickup scan thatstorage position. As shown in FIG. 10C, each set of VOB positioninformation in the present embodiment is expressed using as a “VOBreproduction time”, a “VOB offset”, and a “No. of blocks in VOB”. Whenreading a VOB, the disc reproduction apparatus uses the offset numbersincluded in the VOB position information and calculates the logicalblock number of the logical blocks in which the VOB is stored, beforehaving the optical pickup scan only the number of logical blocksindicated by the “No. of blocks” on the track of the optical disc.

The PGC link information is information which shows what reproductionroute continues after the present logical block, and stores linkdestination information which shows what set of PGC information shouldbe next read into the buffer. When the reproduction according to one setof PGC information is completed by the disc reproduction apparatus, thenext set of PGC information is determined in accordance with the “PGClink information”, and this next set of PGC information is read from thedisc and overwritten into the buffer. In this way, the PGC informationis updated and reproduction control can continue in accordance with thereproduction route indicated by this updated set of PGC information.Here, for the example shown in FIG. 10A, only PGC information #2includes a branch destination (PGC information #13), with the PGC linkinformation of the other sets of PGC information being set at “NULL”.This means that only PGC information #2 has a fixed link destination.

The PG map is information which shows how VOBs to be reproduced by thepresent PGC information are grouped together into chapters, and has adata construction in the form of a table which shows the correspondencebetween the plurality of PG numbers indicated by the arrow a10, and theentry VOBs. Here, a PG (program) is a collection of the plurality ofVOBs given in reproduction order by the present PGC information whichare grouped together in a single chapter, with an entry VOB being a VOBpositioned at the start of a PG.

As one example, PGC information#10 sets a reproduction order to nineVOBs which are numbered VOB#1, #2, #3, #4 . . . #9, with VOB#1 being setas the entry VOB for chapter number PG1, VOB#3 being set as the entryVOB for chapter number PG2, and VOB#6 being set as the entry VOB forchapter number PG3. By doing so, VOB#1 and #2 are grouped together intochapter PG1, VOB#3 to #5 are grouped together into chapter PG2, andVOB#6 to #9 are grouped together into chapter PG3. When a chapter numberis directly inputted into the disc reproduction apparatus via a remotecontroller or a control panel, the PG number for the indicated chapternumber is found, and retrieval is commenced starting from the Entry VOBof the corresponding PG number.

For the example shown in FIG. 10A, an entry VOB for a chapter number areonly written in PGC information #1, with “NULL” being written into PGCinformation #2, #3, #4, #5 and #6. This is because of the premise thatthe search operations using chapter numbers are performed using only PGCinformation #1.

The PGC standard information is made up of the number of repetitions,which shows the number of times the sequence of VOBs written in the VOBposition information is repeatedly retrieved, and a flag which showswhether the VOBs are randomly selected during this repetitive retrieval.

For the example shown in FIG. 10A, “5Loop Random” and “3Loop Random” arewritten in PGC information #3 and PGC information #4, respectively, with“NULL” having been written in the other sets of PGC information. Here,“Random” is attribute information which is an indication for randomretrieval. If the standard information is set as described above, theretrieval of the VOBs indicated by the VOB position information of PGC#3is performed five times, with the VOB to be retrieved in these fiverepetitions being randomly selected.

The PGC command table stores various kinds of commands which includeconditional branch commands which are added to the “VOB positioninformation table”. By executing the commands which are written herebefore and after the retrieval of VOBs based on the VOB positioninformation table, the disc reproduction apparatus can perform a moredynamic switching of reproduction routes.

The conditional branch commands shown in the present figure areexpressed as comparisons to see whether the values of general registersand immediate values are equal or higher/lower, with the branchdestinations being expressed as PGC numbers. Here, general registers areregisters for storing values in accordance with operations made by theuser during reproduction, and are used to inform the disc reproductionapparatus of user operations which have been made using a remotecontroller or a control panel.

For the example shown in FIG. 10A, a PGC command table has been writteninto PGC information #5 and PGC information #6, while the word “NULL”has been written into each of PGC information #1 to #4. This shows thatfor PGC information #5 and #6, determination of a branch destination isbased on commands.

The PGC command table of PGC information #5 stores “CmpRegLink R1, 3,“=”, “PGC#15” and “CmpRegLink R1, 4, “=”, PGC#16”. The former of thesecommands shows that the PGC information #15 is selected as a branchdestination when the stored value of the general register R1 inside thedisc reproduction apparatus is equal to “3”. In the same way, the latterof the commands shows that the PGC information #16 is selected as thebranch destination when the stored value of the general register R1inside the disc reproduction apparatus is equal to “4”.

The PGC command table of PGC information #6 stores “Title Play Title#5”which indicates that the title of title number #5 is the branchdestination of PGC information #6.

(1.1.2) Logical Construction-Video Manager

The Video Manager is made up of VTS internal title search pointers,video objects, and sets of PGC information, with it being possible forits data construction to be standardized to that of the Video Title Set(although it should be obvious that it is far more simplified than thatof the Video Title Set). The difference between the VOBs for the VideoManager and the VOBs for the Video Title Set lies in the fact that theVideo Manager is used exclusively for reproducing the volume menu. Here,the expression “volume menu” refers to a menu in which all of the titlesstored on the optical disc are recorded, so that when the volume menu isdisplayed, the user can select one of the titles. When an optical discis loaded into the disc reproduction apparatus, this volume menu isdisplayed on the screen immediately after the optical pickup has movedfrom the volume management area to the file area.

Since the Video Manager is only used for the volume menu, there are thefollowing two differences between the Video Manager and the Video TitleSet. Firstly, while the VOBs in the Video Title Set include video datafor actual footage, sub-picture data and audio data, the VOBs in theVideo Manager only contain a video pack, a sub-picture pack and amanagement information pack for a background image for a menu. Secondly,the branch destinations of the branch commands in the PGC informationand the management information of the Video Title Set, with certainexceptions, do not exceed the range of the Video Title Set, while thebranch commands in the Video Manager have branch addresses for titles ina variety of Video Title Sets on the optical disc, so that they cancross over between Video Title Sets.

The most significant characteristic of the Video Manager is that it isloaded into a memory provided in the disc reproduction apparatus for theduration that the optical disc is loaded in the disc reproductionapparatus. By having the video Manager stored in memory in this way, thedisc reproduction apparatus can refer to the content of the VideoManager without performing a disc access operation.

FIG. 11 shows the data construction of the Video Manager. As shown inthis figure, the Video Manager is composed of “VOBs for menu”, “menu PGCinformation”, and a “VM internal title search pointer table”.

The “VOBs for menu” are VOBs which are specially used for the volumemenu. As their name suggests, they include the sub-picture pack fordisplaying the volume menu and the management information pack forperforming reproduction control in accordance with cursor operations andconfirmation operations. The display image for a volume menu is shown inFIG. 12. The VOB for the volume menu includes a sub-picture pack inwhich character strings showing the titles have been subjected torun-length encoding, the titles being “Action movie A: General releaseversion”, “Action movie A: Digest”, “Action movie A: Profile Quiz”,“Action movie A: TV broadcast version”, “Action movie A. Multi-storyversion”, and “Action movie A: Multimedia book”. The user selects one ofthese title name character strings and performs a confirmation-operationto indicate the title to be reproduced. Here, the management informationpack in the same VOB includes a same number of sets of item informationas there are titles, as shown in FIG. 13. These sets of item informationstore a “Title Play” command which indicates a branch to each titlenumber and a “palette conversion range” which shows the area on thedisplay whose color will change when the corresponding item is in theselection condition.

The set of “menu PGC information” (shown as PGC information for Menu inthe drawings) is a set of PGC information which is exclusively used forthe volume menu, and stores the recording position of the correspondingmenu VOB so that the menu VOB can be read when the optical disc isloaded into the disc reproduction apparatus. This set of PGC informationis read by the disc reproduction apparatus immediately after the dischas been loaded in the disc reproduction apparatus and the opticalpickup has moved from the volume management area to the file area, andis used to guide the optical pickup so as to read the menu VOB. In thisway, the volume menu can be displayed on the screen.

The VM internal title search pointer table is made up of a plurality ofVM internal title search pointers #1 . . . #99 which each correspond toa title number. An example of this table is shown in FIG. 14. In thisfigure, the VM internal title search pointer #1 corresponds to titlenumber 1, with VM internal title search pointers #2 and #3 respectivelycorresponding to title numbers 2 and 3.

VM internal title search pointer #1 includes a pairing of a Video TitleSet number and a VTS internal title number, in addition to a “titleplayback type”. Here, a “title playback type” is information forimmediately informing the disc reproduction apparatus, when a selectionhas been made from the volume menu, of the classification of thecorresponding title in the VM title search pointer table.

Here, the disc reproduction apparatus is informed of the species typeinto which the selected title has been classified immediately after thetitle is selected from the volume menu, since it is too late to havesuch classification established after reproduction of the title hasstarted. This is necessary in order to have the disc reproductionapparatus perform a certain process in a very short period of time. Thisprocess is the recognition by the disc reproduction apparatus of whetheremulated AV functions are possible. This recognition needs to beperformed in such a short time since it is necessary to have presentreproduction time “00:00:00” and chapter number “00” displayed on thepanel provided on the disc reproduction apparatus immediately after theuser has loaded the optical disc into the disc reproduction apparatusand has performed a title selection operation. This is also necessarysince there is the possibility of the user attempting to perform achapter search operation and time search operation immediately afterperforming the title selection operation.

If, on the other hand, the recognition of whether to perform emulated AVfunctions takes is too slow, it will not be completed within the shortperiod of time described above, so that the display of the presentreproduction time “00:00:00” and the chapter number “00” will not bemade in time for the start of reproduction, or the disc reproductionapparatus will not be able to respond to chapter search operations andtime search operations made for a title immediately after titleselection.

Here, in order to determine whether emulated AV functions are possiblefor a title, it is necessary to recognize the classification to whichthe selected title belongs. The recognition of this classification ismade by determining the “number of sets of route information”, the“presence of loops”, and the “presence of automatic branches”, which isperformed by judging whether there is any link destination PGCinformation in the link PGC information, whether there is anyconditional branch information in the PGC command table, and whetherthere are any loop attributes in the PGC standard information. However,since the sets of PGC information are distributed within the Video TitleSet management information of each Video Title Set, it is necessary forthe disc reproduction apparatus in making this judgment to write intomemory the management information of the Video Title Set which storesthe title that has been selected by the user. If such access to theVideo Title Set is necessary, then the display of the presentreproduction time “00:00:00” and the title search number “00” will bedelayed by the time taken by this access.

Also, to properly determine the “presence of branches”, it is necessaryto check that no branch commands are present in any of the PCI packetsin the large number of management information packs which compose oneVOB. However, since the size of each VOB is in the region of severalmegabytes, it is extremely difficult to perform this checking ofmanagement information packs in a very short period of time.

In view of these problems, a “title playback type” which classifies eachtitle into one of the groups is provided beforehand in the VM internaltitle search pointer table, so that the disc reproduction apparatus canbe informed, as soon as a title is selected, of the group to which theselected title belongs.

The title playback type includes a plurality of flags for showing theformat of the various titles. The reference numerals a141, a142, anda143 shown in the figures indicate the “sequential single PGCidentification flag”, the “no branch flag” and the “no branch betweentitles” flag, with these flags being set at “On” or “Off” to indicatethe format of each title.

When the “single sequential PGC identification” flag is “On”, the titleselected by the user is expressed by only one set of PGC informationwhich indicates all of the VOBs from the opening scene to the endingscene. When it is “Off”, the VOBs from the opening scene to the endingscene are expressed by several sets of PGC information or loopinformation indicating that the set of VOBs are repeatedly read a numberof times is included in the PGC standard information. For the exampleshown in FIG. 14, the “sequential single PGC identification” flag isonly “On” for the VM internal title search pointer #1, with the “Off”state of the “sequential single PGC identification” flag for the VMinternal title search pointers #2 and #3 showing that out of the titlenames displayed in the list in the volume menu, only the “Action movieA: General release version” of title number 1 is expressed by one set ofPGC information indicating all of the VOBs from the opening scene to theending scene.

When the “no branch” flag is “On”, this shows that there are absolutelyno branch commands for branching to another set of PGC information ineither the PGC command field of the PGCs included in the title, or inany of the hundreds or thousands of management information packs in theVOBs of several megabytes in length which are indicated in the retrievalorder shown in the sets of PGC information for the title. For theexample shown in FIG. 14, the “no branch” flag is “Off” for VM internaltitle search pointers #2 to #9, while the “no branch” flag is “On” forVM internal title search pointer #1. This arises since for the case ofvideo title “Action movie A: General release version” corresponding toVM internal title search pointer #1, PGC information #1, which is theEntry-PGC information for Video Title Set V1, does not contain anybranch commands in its PGC command field or link information, and noneof the VOBS whose retrieval is specified by the VOB position informationinclude branch commands.

For VM internal title search pointer #5, on the other hand, the “nobranch” flag is “Off”, since the video title “Action movie A:multi-story version” corresponding to VM internal title search pointer#5 has Entry-PGC information, PGC information #5, in Video Title Set V1which includes a conditional branch command whose execution depends onthe stored value of register R1.

It should be noted here that while the present description deals withthe case when one flag is used to indicate the presence (or not) ofbranches, a plurality of flags which correspond to different kinds ofbranches may be used. Here, these “different kinds of branches” refersto branches which are performed in response to confirmation operationsby the user and to branches which are automatically performed regardlessof such confirmation operations. The former kind of branches are called“manual branches”, and the latter kind are called “automatic branches”.If this is the case, titles for which there are absolutely noconditional branch commands (which indicate a branch to another set ofPGC information in accordance with a confirmation operation for an item)in the PGC command field of the PGC information or in the very manymanagement information packs in the VOBs in the retrieval order given inthe PGC information have a “no manual branch” flag set at “On”.

In the same way, titles for which there are absolutely no automaticbranch commands (which indicate an automatic branch to another set ofPGC information) in the PGC command field of the PGC information or inthe very many management information packs in the VOBs in the retrievalorder given in the PGC information have a “no automatic branch” flag setat “On”.

By creating the above distinction using the “no manual branch” flag andthe “no automatic branch” flag, the route construction of titles can bemore described more precisely.

The “no branch between titles” flag is a flag for showing whether anybranches to another title occur during the reproduction of a title,aside from when a title number is selected. More specifically, the “nobranch between titles” flag guarantees that the command fields in theitems of the management information packs and the command fields in PGCinformation definitely do not contain any branch instructions whichbranch to another title.

(2.1) Outline of the Disc Reproduction Device

The following is an explanation of the disc reproduction apparatus ofthe present invention. In general, disc reproduction apparatuses can beclassified into two types which are low-cost players, which are equippedwith low capacity memories and whose processing speed is slow, andprofessional players, which are equipped with large memories and whoseprocessing speed is on a par with specialized equipment. In thisembodiment, an example of a low-cost player is described. A perspectivedrawing in of this low-cost player (hereinafter referred to as DVDplayer 1), a television monitor 2, and a remoter controller 91 is shownin FIG. 15.

DVD player 1 has an opening in the front of its case and has a drivemechanism where a disc is inserted provided inside this opening.

A remote control receiving unit 92, which includes detecting elementsfor detecting the infra-red signals emitted by the remote controller 91,is provided on the front of the DVD player 1, so that when the usermakes an operation with the remote controller 91 in his/her hand, theremote control receiving unit 92 generates an interrupt signal whichindicates the inputted key.

A video output terminal and an audio output terminal are provided on theback of the DVD player 1, so that when these terminals are connected toa standard large-screen (33- or 35-inch) television using AV leads, avideo signal read from a DVD can be enjoyed by the user. As can beunderstood from the above description, the DVD player 1 in the presentembodiment is not connected to a personal computer, and is instead astandard domestic appliance which is to be used with a television as amonitor.

The remote controller 91 is used for receiving user operations. Anexample of the key arrangement on the remote controller 91 is shown inFIG. 16. Here, the ten key 911 is used in combination with the otherkeys for numerical input. The cursor keys 912 arranged in a cross areaused for changing the selected item. The “ENTER” key is used forperforming the confirmation of selections. To make a search indication,the “CHAPTER” or “TIME” keys is pressed, the numerical input becomespossible and a numerical input made using the ten key 911 is displayedon the display unit 913. If the user presses the “CHAPTER” or “TIME” keyagain, a time or chapter search is performed in accordance with the userindication. The “TITLE PROGRAM” key and “PROGRAM” key are also providedfor indicating program reproduction, with a pressing of these keys alsomaking numerical input possible, so that if a number showing thereproduction order is inputted using the ten key and a same program keyis pressed, the reproduction command is confirmed. Using the “TITLEPROGRAM” key, the user can indicate programmed reproduction for a title,while the “PROGRAM” key is used to indicate programmed reproduction fora chapter. As one example, if the user presses the “TITLE PROGRAM” keyand the reproduction order “3”, “4”, “2” using the ten key, title number“3”, title number “4”, and title number “2” are reproduced in thatorder.

(2.2) Construction Elements of the Disc Reproduction Device

FIG. 15 is a block diagram showing the construction of the DVD playerused in the present embodiment. The DVD player includes a drivemechanism 16, an optical pickup, a mechanism control unit 83, a signalprocessing unit 84, an AV decoding unit 85, a remote control receivingunit 92, and a system control unit 93. AV decoding unit 85 comprises asignal separating unit 86, a video decoder 87, a sub-picture decoder 88,audio decoder 89, a state display unit 209, and a picture mixing unit90.

The remote control receiving unit 92 receives a key signal which isinfra-red transmitted when in a key on the remote controller 91 ispressed, and generates in interrupt signal showing the pressed key tonotify the system control unit 93 of the pressed key as a “receptioninstruction”. Here, the kinds of reception instructions which can beused to notify the system control unit 93 include start reproductioninstructions, stop reproduction instructions, button selectioninstructions, button confirmation instructions, chapter searchinstructions for an indicated chapter number, time search instructionsfor an indicated time, chapter program instructions including areproduction order indication for chapters, and title programinstructions including a reproduction order indication for titles.

The state display unit 209 is a display unit which is composed of aliquid crystal panel, or the like, that is provided on the front of theDVD player 1. The state display unit 209 controls the liquid crystaldisplay in accordance with the indications from the system control unit93, so as to display the title number of the title being reproduced, thechapter number, and the present reproduction time. On receiving adisplay invalidating signal from the system control unit 93, the statedisplay unit 209 terminates the display of title number, chapter numberand reproduction time. Here, it should be also noted that it is alsopossible for the state display unit 209 to be constructed to displayonly one of title number, chapter number, and reproduction time.

The drive mechanism 16 is comprises a platter on which an optical discis placed and spindle motor 81 for rotating the inserted optical disc.The platter can be moved in and out of the DVD player by means of aneject mechanism which is not shown in the drawing. The user places anoptical disc on the platter when it has been projected forward outsidethe DVD player. After this, the platter is moved back into the DVDplayer so as to load the optical disc.

The mechanism control unit 83 controls the spindle motor 81 for rotatingthe disc and the mechanism made up of the optical pickup for reading thesignal from the disc and actuator 82 of the optical pickup.Specifically, the mechanism control unit 83 adjusts the motor speedaccording to a track position specified by system control unit 93. Atthe same time, it moves the optical pickup by controlling the actuator82 of the pickup and, having detected a correct track by servo control,waits for a desired physical sector before reading signals continuouslystarting from desired position.

The signal processing unit 84 converts the signals read using theoptical pickup into a sequence of digital data while performing variousprocesses such as amplification, waveform shaping, conversion to binary,demodulation, and error correction. It then stores the processed data ina buffer memory inside the system control unit 93 in logical blockunits.

The AV decoding unit 85 applies certain processes to the digital datainputted as VOBs and converts them into the video signals and audiosignals.

The signal separating unit 86 receives the digital data transferred fromthe buffer memory in units of logical blocks (packets), and classifiesthe data into packs of management information data, video data,sub-picture data, or audio data by identifying the stream ID andsub-stream ID of each packet. The signal separating unit 86 outputsvideo data to the video decoder 87, audio data to the audio data decoder89, and sub-picture data to the sub-picture decoder 88. The signalseparating unit 86 also outputs management information packs to thesystem control unit 93. When such data is outputted, the system controlunit 93 indicates numbers to the signal separating unit 86, with, asshown in FIG. 6, these number indicating one set of audio data (A, B, orC) and one set of sub-picture data (A or B). On receiving theseindications from the system control unit 93, the signal separating unit86 outputs only the data on the specified channels to the audio decoder89 and the sub-picture decoder 89. The data on the other channels isdiscarded.

(2.2.1) Disc: Reproduction Device . . . Construction of SignalSeparating unit 86

FIG. 18 is a block diagram showing the construction of the signalseparating unit 86. As shown in the drawing, the signal separating unit86 comprises an MPEG decoder 120, a sub-picture/audio separating unit121, a sub-picture selecting unit 122, and an audio selecting unit 123.

The MPEG decoder 120 determines the types of packs transferred from thebuffer memory by checking the stream IDs and outputting the packets asfollows. If the stream ID is “1110 0000”, the MPEG decoder 120 outputsthe packet to the video decoder 87. If the stream ID is “1011 1101”, theMPEG decoder outputs the packet to the sub-picture/audio separating unit121. Alternatively, if the stream ID is “1011 1111”, the MPEG decoder120 outputs the packet to the system control unit 93.

The sub-picture/audio separating unit 121 outputs the packets input fromthe MPEG decoder 120 to the sub-picture selecting unit 122 if theirsub-stream ID is “001* **** or to the audio selecting unit 123 if theirsub-stream ID is “1010 0***”. As a result, each set of sub-picture dataand audio data is appropriately output to either the sub-pictureselecting unit 122 or the audio selecting unit 123.

The sub-picture selecting unit 122 outputs the sub-picture data on thechannel number specified by the system control unit 93 to thesub-picture decoder 88 and discards the rest of the sub-picture data.If, as in the example of FIG. 6, sub-picture materials for channels Aand B are respectively English and French subtitles, then aspecification of channel A by the system control unit 93 will result inthe sub-picture selecting unit 122 outputting the sub-picture data onchannel A to sub-picture decoder 88, with the sub-picture data onchannel B being discarded. As a result, the sub-picture decoder 88decodes only the English subtitles.

The audio selecting unit 123 outputs the audio data on the channelnumber specified by system control unit 93 to the audio decoder 89 anddiscards the rest of the audio data. If, for the example shown in FIG.6, the audio material on channels A, B, and C are English, French, andJapanese soundtracks, then a specification of channel A by the systemcontrol unit 93 will result in the audio selecting unit 123 outputtingthe audio data on channel A to the audio decoder 89, with audio packetsB and C being discarded. As a result, the audio decoder 89 decodes onlythe English soundtrack,

The video decoder 87 decodes and decompresses the video data sent fromthe signal separating unit 86, before outputting the data to the picturemixing unit 90 as a digital video signal.

The sub-picture decoder 88 decodes and decompresses the sub-picture datasent from the signal separating unit 86 if the sub-picture data is imagedata compressed with run-length compression, and outputs the sub-picturedata to the picture mixing unit 90 in the same format as the videosignals. Here, if the image data is provided with a plurality of itemsand the user moves the cursor between these items, the system controlunit 93 instructs the sub-picture decoder 88 to change the color of theimage data in question. Such color changing indications are outputtedbased on the item color information recorded in the Highlightinformation, so that the display of items can be changed to theselection color or the confirmation color. Here, movement of the cursoramong these items is displayed to the user by changing the selectioncolor and confirmation color.

The description of the construction of the DVD player 1 continues withreference to FIG. 17. The audio decoder 89 decodes and extends the audiodata sent from signal separating unit 86 before outputting digital audiosignal.

The picture mixing unit 90 outputs a video signal after mixing theoutputs from video decoder 87 and sub-picture decoder 88 according tothe ratio specified by system controlling unit 93. This mixing ratio isdetermined based on the contrast given in the item color information inthe Highlight Information, and can be changed for each GOP unit. Thepicture signals are converted to an NTSC (National Television SystemCommittee) video signal which is then inputted into the TV monitor 2.

(2.2.2) Disc Reproduction Device . . . Construction of System ControlUnit 93

The following is an explanation of the internal construction of thesystem control unit 93 which is shown in FIG. 19. As shown in thefigure, the system control unit is made up of a remote control inputinterpreting unit 71, a reproduction control unit 72, a button controlunit 73, a command interpreting/executing unit 74, a buffer memory 94, asystem state management unit 750, and a valid function determining unit760.

The buffer memory 94 is used for storing the data which has beensubjected to the various processes such as amplification, waveformshaping, conversion to binary, demodulation, and error correction. Ifthe data written into the buffer memory 94 is Video Title Set managementinformation, it is written into another buffer which is not illustrated.On the other hand, if the data is a VOB, the system control unit 93transfers the data one pack at a time to the signal separating unit 86.By when VOBs are transferred in this way, the management informationpacks will be sent beck from the AV decoder unit 85.

The remote controller input interpreting unit 71 interprets the remotecontrol key data received by the remote control receiving unit 82. Thisinterpreted remote control key data can be a start reproductioninstruction, a stop reproduction instruction, button selectioninstruction, a button confirmation instruction, a chapter searchinstruction for an indicated chapter number, a time search instructionfor an indicated time, a chapter program instruction including areproduction order indication for chapters, or a title programinstruction including a reproduction order indication for titles. Ofthese, button selection instructions and button confirmationinstructions are outputted to the button control unit 73, while startreproduction instructions, stop reproduction instructions, chaptersearch instructions, time search instructions, chapter programinstructions, and title program instructions are outputted to thereproduction control unit 72.

The button control unit 73 stores the management information pack of theVOB which is being reproduced which it receives from the AV decoder unit85, and, when a button selection instruction and a button confirmationinstruction are received from the remote controller input interpretingunit 71, outputs a control signal to the AV decoder unit 85 for changingthe color of the sub-picture in a screen area assigned to the button tothe confirmation color in accordance with the Highlight information inthe PCI packet of the stored management information pack. Also, when abutton confirmation instruction is received, is sends the commandassigned to the selected button to the command interpreting/executingunit 74.

The command interpreting/executing unit 74 interprets the commandinputted from the button control unit 73 and, if there is a change ofPGC information which changes the reproduction route, the commandinterpreting/executing unit 74 outputs a reproduction controlinstruction notifying reproduction control unit 72 of the new PGCinformation, as well as outputting a system state control instructionnotifying the system state management unit when there has been a changeto the state parameters stored inside the system.

The valid function determining unit 760 is made up of a routeinformation flag storage unit 761, a route information flag storage unit762, and a permitted function table 763.

The route information flag storage unit 761 stores the “sequentialsingle PGC identification” flag.

The route information flag storage unit 762 stores the “no branch” flagand the “no branch between titles” flag.

The permitted function table 763 stores the necessary combinations ofthe set states of the flags in the route information flag storage unit761 and the route information flag storage unit 762 for each of achapter number display function, a reproduction time display function, achapter number search function, a time search function, a chapterprogramming function, and a title programming function to be permitted.An example of this permitted function table is shown in FIG. 20. Asshown in this figure, the chapter number display function, thereproduction time display function, the chapter number search function,the time search function, and the chapter programming function are onlypermitted when both the “sequential single PGC identification” flag andthe “no branch” flag are “On”. In the same way, the title programmingfunction is only permitted when the “sequential single PGCidentification” flag and the “no branch between titles” flag are “On”.

The system state management unit 750 includes a group of state registers751 which is made up of all kinds of registers showing the present stateof the disc reproduction apparatus, a video manager buffer 752 intowhich the Video Manager is loaded, and a PGC information buffer 753 intowhich the PGC information which is presently being used is loaded. Here,the group of state registers 751 is made up of an audio channelregister, a sub-picture register, a PGC number register, a programnumber register, an index number register, a chapter number register,and a reproduction elapsed time register.

The audio channel register is used to store the audio channel numberwhich is presently valid, with the sub-picture channel register storingthe sub-picture channel number which is presently valid, with thesenumbers being outputted as a control signal to the AV decoder unit 85 toindicate the present audio channel and sub-picture channel. Whenreproduction is commenced by the reproduction control unit 72, the titlenumber of the title being reproduced is stored in the title numberregister. At the same time, the number of the Entry-PGC information forthe chosen title is stored in the PGC number register. Here also, whenthe reproduction of VOBs n the reproduction order indicated by the PGCinformation determined by the reproduction control unit 72, the programnumber of the classification number of the VOB which is presently beingreproduced is stored in the program number register.

The chapter number register is used to store the chapter number, whilethe reproduction elapsed time register is used to store the elapsedreproduction time. The title number register stores the title number.While reproduction is being performed, the values stored by theseregisters are updated as is required. When such updating is performed, acontrol signal showing the updated value is outputted to the statedisplay unit 209.

FIGS. 21A-21D and 22A-22D are flowcharts for the processing of thesystem control unit 93. The operation of DVD player will be explainedbelow with reference to these figures.

When the user presses the eject button on DVD player 1, the platter ismoved outside of the cover. When a user places an optical disc on thisplatter, the platter is then moved back into the DVD player 1 to loadthe disc. As shown in step S121 of FIG. 21A, the system control unit 93is first waits for a disc to be inserted, and, on detecting that a dischas been loaded using an optical sensor or the like, controls themechanism control unit 83 and the signal processing unit 84 to performrotation control with the optical pickup is positioned in the lead-inregion. This operation continues until stabilized rotation has beenachieved, at which point the optical pickup is moved outward from thelead-in region and reads the volume management area. Based on theinformation in this volume management area, the video manager is writteninto the video manager buffer 752 (step S122). The system control unit93 also calculates the storage address of the PGC information for thevolume menu, and writes the PGC information into the PGC informationbuffer (step S123). Since this PGC information is for the volume menu,it is stored in the buffer, so that the system control unit 93 can referto its content and calculate the storage address of the VOBs to bereproduced for the menu. Once the VOB to be reproduced is decided, thesystem control unit 93 outputs a control signal to the mechanism controlunit 83 and to the signal control unit 84 and has the determined VOBsread from the optical disc. As a result, a volume menu, such as thatshown in FIG. 12, is displayed on the TV monitor 2 (step S124). Whenthis volume menu is displayed, the reproduction control unit 72 waitsfor the selection of a title number (step S125).

Here, the user views the list of titles and confirms a selection ofhis/her desired title number. The state display unit 209 is then made todisplay the selected title number (step S126), and the Highlightcommand, “PlayTitle”, which is stored corresponding to the selectedtitle number is read. Following this, in step S127 the VTS number #i andthe VTS internal title number #j are read from the title search pointer#k corresponding to the title number #k indicated by the operands of the“PlayTitle” command. In step S128, the title playback type #k is readfrom the title search pointer #k corresponding to the selected titlenumber #k. In step S129, it is judged whether the “sequential single PGCidentification” flag is “On”, and in step S130 it is judged whether the“no branch” flag is “On”. These judgments are to confirm that title #kis a single sequential title, so that if either of the flags is “off”, a“No” judgment will be given and the processing will advance to stepS135, where a “Chapter display and time display not possible” message isdisplayed together with the title number. In this case, in step S132,the state display unit 209 is deactivated and the processing advances tostep S133. Note here that the display in step S135 is merely a displayof information to the user, so that this step may be omitted.

When both of the flags are judged as being “On” in steps S129 and S130,the processing advances to step S131 where the time display of the statedisplay unit 209 is reset to “00:00:00” and the chapter display is resetto “00”, with the processing then advancing to step S133. In step S133,the title number #j and the number of the Entry-PGC information numberare read from the title search pointer of the video title set indicatedby the VTS number #i and are written into the group of state registers751. The route processing routine is then called in step S134 with thePGC information #k read in this way as the Entry-PGC information.

FIG. 21B is the flowchart for the route processing routine. In thisfigure, the “VOB pointer” indicates the VOB to be read out of the VOBposition information in the PGC information stored in the PGCinformation buffer 753, while the “block pointer” indicates the logicalblock which is presently being read in the VOB indicated by the VOBpointer. In step S141, the VOB pointer is initialized, which is to sayset to the first VOB in the VOB position information table of the PGCinformation #k. In step S142, the block pointer is initialized, which isto say set at the first logical block in VOB#i indicated by the VOBpointer. Next, in step S143, a check is performed to see whether anevent has been caused by a user operation, and if not, in step S144, themechanism control unit and the signal processing unit are activated toread the logical block indicated by the block pointer. Here, since eachVOB is made up of a plurality of VOB units which each have a managementinformation pack at the front, a management information pack is readfirst by the signal processing unit 84. The signal processing unitsubjects the signal read by the optical pickup to the variety ofprocesses described above, and the processed data is stored in logicalblock units in the buffer memory inside the system control unit 93. Thesignal separating unit 86 receives the packs transmitted from the buffermemory and refers to the stream ID and substream ID in the header ofeach pack to detect whether each pack is a management information pack.Here, detected management information packs are outputted to the systemcontrol unit 93.

The reproduction control unit 72 sets the transfer rate and buffer sizeincluded in each management information pack and prepares for thedecoding of the video pack, audio pack, and sub-picture pack whichfollow the management information pack in question.

Next, in step S145, the reproduction control unit 72 judges whether theblock pointer is indicating the final logical block in VOB#i, and ifnot, the processing advances to step S146 where the variable j isincremented by one and to step S147 where the block pointer is updatedto the jth logical block in VOB#i. After this, the processing advancesto step S148 in FIG. 21C.

In step S148 in FIG. 21C, a judgment as to whether the pack readaccording to the indication of the block pointer is a managementinformation pack and whether the DSI packet included in this managementinformation pack is one second long. This is performed since it isnecessary to update the time display on the state display unit 209 insynchronization with the reading of management information packs whichare provided at the front of 0.5 second-long VOB units. Here, if thereading of a VOB has just begun, the display of the state display unit209 will not be updated, while when the reading has progressed and a DSIpacket which is one second long has been read, the time display of thestate display unit will be advanced by one second.

By repeating the processes in steps S143 to S147 the time display can beupdated, with the video, audio, and sub-picture packs which compose theVOB being successively read. The signal read from the disc is processedby the signal processing unit 84 and is stored in logical block units inthe buffer memory of the system control unit 93. Packs are thentransmitted from the buffer memory to the signal separating unit 86 andthe stream ID and substream ID in the header of each pack is judged.

For video packs, the MPEG decoder 120 judges whether the stream ID is“1110 0000” and outputs the packs to the video decoder 87. The videodecoder 87 decodes the packs according to MPEG methods and having waitedan appropriate time according to the SCR and PTS, outputs the decodedimage signal to the picture mixing unit 90.

For sub-picture packs, the MPEG decoder 120 judges whether the stream IDis “1011 1101” and whether the first three bits of the substream ID are“001”, and outputs the packs to the sub-picture decoder 88. Thesub-picture decoder 88 decodes the packs according to run-lengthdecoding and having waited an appropriate time according to the SCR andPTS, outputs the decoded image signal to the picture mixing unit 90.

The outputs of the video decoder 87 and the sub-picture decoder 88 aremixed by the picture mixing unit 90 according to the mixing ratiospecified by the system control unit 93. This mixed image signal is thenconverted to an analog signal and is outputted to the TV monitor 2.

As a result of the repetition of the above process, the block pointerends up indicating the final logical block in the current VOB, so thatthe judgment “Yes” is given in step S145 and the processing advances tostep S151. In step S151, it is determined whether the VOB pointer isindicating the final VOB in the VOB position information table for PGCinformation #k, and if not, the processing advances to step S152 wherethe variable i is incremented, and then to step S153 where the VOBposition information is advanced to the next VOB in the VOB positioninformation in PGC information #k. Following this, the processing movesto step S154 in FIG. 21D.

It should be noted here that when the VOB pointer is advanced to thenext VOB, there is the possibility that the VOB newly indicated by theVOB pointer is the Entry-VOB for a program. A judgment to see whetherthis is the case is performed by the reproduction control unit 72 instep S154, with the judgment “Yes” resulting in the processing advancingto step S155 in FIG. 21D, where the chapter display by the state displayunit 209 is advanced by one before the processing returns to step S142.Following this, the processing in steps S142-S147 is performed for thenewly indicated VOB.

When it is judged in step S151 that the VOB pointer is indicating thefinal VOB in the VOB position information, this means that the presentreproduction route has been completed. At this point, a check isperformed to see if there is a post-processing command in the PGCinformation stored in the PGC information buffer 753. If there is, thebranch destination PGC information #k is determined according to thispost-processing command, or if not, the branch destination PGCinformation #k is determined according to the PGC link information,before the route processing routine is recurrently called in step S158.

Processing of Reproduction Control Unit 72 for a Chapter Search

The following explanation deals with the case when the user makes achapter search operation while reproduction is being performed asdescribed above. In this case, the judgment “Yes” is given in step S143and the processing advances to step S161 in FIG. 22A. In step S161, ajudgment is made as to whether the chapter search key was pressed, inwhich case the processing advances to step S162. In steps S162, S163,judgments are made to see whether the “sequential single PGCidentification” flag and the “no branch” flag are “On”, and, if eitherof these flags is “Off”, the processing advances to step S169 where themessage “Chapter search function not available due to interactivereproduction” is displayed, before returning to step S144. As mentionedbefore, such display is not essential to the operation, and so may beomitted.

When both flags are “On”, in step S164 the system waits for an inputfrom the ten key 911. If the user presses the “8” key on the remotecontroller 91, the result “Yes” is given in step S164, and, in stepS165, the inputted ten key code “8” is converted in program number “8”.This program number “8” is then converted into an Entry VOB number #s,and in step S167 the converted Entry VOB number #s is set in the VOBpointer. In step S168, the first address in the Entry VOB number #s isset in the block pointer. After the pointers have been set in this way,the processing returns to step S144, where the indicated logical blockis read by the mechanism control unit and signal processing unit asbefore.

Processing of Reproduction Control Unit 72 for a Time Search

The following explanation deals with the case when the user makes a timesearch operation while reproduction is being performed as describedabove. In this case, the judgment “Yes” is given in step S143 and theprocessing advances to step S161 in FIG. 22A. In step S161, a judgmentis made as to whether the chapter search key was pressed, which is notthe case, so that the processing advances to step S171. In step S171, ajudgment is made as to whether the time search key has been pressed,and, since this is the case, the processing advances to step S172. Insteps S172, S173, judgments are made to see whether the “sequentialsingle PGC identification” flag and the “no branch” flag are “On”, and,if either of these flags is “Off”, the processing advances to step S179where the message “Time search function not available due to interactivereproduction” is displayed, before returning to step S144. As mentionedbefore, such display is not essential to the operation, and so may beomitted.

When both flags are “On”, in step S174 the system waits for an inputfrom the ten key 911. In step S175, the inputted ten key code is thenconverted to time format data written as hr:min:sec. After thisconversion, the reproduction search unit 72 in step S176 converts thetime format data into a VOB number #i and a DSI packet, based on thetime map search table. In step S177, the converted VOB number #i is setin the VOB pointer and in step S178, the converted DSI address is set inthe block pointer. By setting the pointers in this way, reproduction canbe commenced from the reproduction time indicated by the user.

Processing of the Reproduction Control Unit 72 for the ChapterProgramming Function

The following is an explanation of when a user makes a chapterprogramming function operation during the reproduction of VOBs using theremote controller 91. When such an operation is received by the remotecontrol receiving unit 92, the judgment “Yes” is made in step S143 ofFIG. 21B and the processing advances to step S161. In step S161, thejudgment as to whether the chapter key has been pressed results in “No”,so that the processing advances to S171. In step S171, the time key hasnot been pressed, so that the judgment “No” is given and the processingadvances to step S180. In step S180, the judgment “Yes” is given, sothat in steps S181 and S182, the system confirms that the “sequentialsingle PGC identification” flag and the “no branch” flag are both “On”.

Here, if both flags are “On”, the processing advances to step S183 wherethe variable k is set at “1”, before the input of a ten key code is madein step S184. Here, the variable k is used to express a value to beadded to the plurality of programs which have been confirmed in theschedule list, while the schedule list refers to a list of the programsto be reproduced by the chapter programming function.

Once a key code has been inputted, the judgment “Yes” is given in stepS184 and the processing advances to step S185.

In step S185, the inputted ten key code #n is converted to a programnumber #n and in step S186 this program number #n is stored as the kthitem in the schedule list. After this, the variable k is incremented byone in step S186 and it is judged in step S188 whether a programmingtermination code has been issued by the remote controller 91. Here, aprogramming termination code is a code to terminate numerical input, sothat as long as no such code is detected in step S188, the processing insteps S184 to S188 will be repeated. By doing so the first, second,third, and later program numbers are stored in the schedule list. If,having entered the program numbers “1”, “3”, “5”, and “7”, the usermakes a programming termination operation, the judgment “Yes” will begiven in step S188 and the processing will advance to step S189. StepsS189 to S199 are made up of a loop process in which VOBs are read inaccordance with the schedule list. In step S189, the variable k and thevariable #s showing the block pointer are reset to “1”, and in stepS190, the first program number #n in the schedule list is converted toan Entry-VOB number #s. Next, this Entry-VOB number #s is set in the VOBpointer and the first address in this Entry-VOB number #s is set in theblock pointer, before the logical blocks in this VOB are read by themechanism control unit and the signal processing unit.

For the above example, the first program number “1” in the schedule listis converted into a Entry-VOB number #s which is set in the VOB pointer.The first address in this Entry-VOB number #s is set in the blockpointer, and the logical blocks in this VOB are read by the mechanismcontrol unit and the signal processing unit.

When the final logical block is indicated by the block pointer, thejudgment “Yes” is given in step S195 and the processing advances to stepS198.

In step S198, it is confirmed that the final VOB of the schedule list isbeing indicated, and if not, in step S199 the variable k is incrementedto indicate a next program number in the schedule list, before theprocessing returns to step S190.

After this, the processing in steps S190 to S197 is repeated for all ofthe remaining program numbers in the schedule list.

Processing of the Reproduction Control Unit 72 for the ChapterProgramming Function

The following is an explanation of when a user makes a title programmingfunction operation during the reproduction of VOBs using the remotecontroller 91. When such an operation is received by the remote controlreceiving unit 92, the judgment “Yes” is made in step S143 of FIG. 21Band the processing advances to step S161. In step S161, the judgment asto whether the chapter key has been pressed results in “No”, so that theprocessing advances to S171. In step S171, the time key has not beenpressed, so that the judgment “No” is given and the processing advancesto step S180. In step S180, the chapter programming key has not beenpressed, so that the judgment “No” is given, and the processing advancesto step S200. In step S200, the title programming key has been pressed,so that the judgment “Yes” is given in step 200 and the processingadvances to step S201, where the variable s is reset to “1”. Thisvariable s is used to express the order of the plurality of titles whichare to be reproduced in the schedule list. This schedule list is a listof the titles which are to be reproduced in the specified order. In stepS202, the system waits for a input from the ten key.

Once there has been an input from the ten key, the inputted ten key code#n is converted into a title number #k, and the title playback type #kis read from the title search pointer #k corresponding to this titlenumber #k. Following this, it is judged whether the “sequential singlePGC identification” flag is “On” for the reproduction type #k. If thisflag is “On” in step S206, the title number #n inputted using the tenkey is set as the first item in the schedule list. Following this, thevariables is incremented in step S208 and in step S209, a check isperformed to see whether the programming termination code has beeninputted, with the processing in steps S202-S209 being repeated untilsuch code is inputted. At such time, the variable k is reset to “1” instep S210, and the first title number #n in the schedule list is read instep S211. In step S212, the VTS number #i and the VTS internal titlenumber #j are read from the title search pointer #n corresponding to theselected title number #n, and in step S213, the title number #j and theEntry-PGC information are read from the title search pointer of thevideo title set #i indicated by the VTS number #i and are written intothe group of state registers 751. After this, the route processingroutine is called with the Entry-PGC information as the PGC information#k.

By calling the route processing routine in this way, the processing inthe route processing routine can be performed for the Entry-PGCinformation for the first title number in the schedule list, before areturn is performed to the present flowchart. A judgment is then made asto all of the title numbers in the schedule list have been read, and ifnot, the variable k is incremented to have the next title number read.

With the disc reproduction apparatus of the present embodiment, animmediate judgment can be made during reproduction execution of anapplication as to whether emulated AV functions, such as feedbackfunctions including display of a present chapter number and presentreproduction time, search functions based on chapter number orreproduction time, a programmed reproduction function using chapternumbers, or a programmed reproduction function using titles,

are possible and when not possible, the system can prohibit the functionto prevent erroneous operation.

For the present embodiment, the display of reproduction elapsed time andchapter number during disc reproduction can be linked to titles, so thatonly valid numbers are displayed. This is to say, display ofreproduction time and chapter numbers is only performed whereappropriate, so that no display is given for unsuitable titles. In thisway, the system does not end up displaying invalid information to theuser.

The present embodiment has described the construction and operation of alow-cost player although it should be obvious that a variety of othertypes of player, such as professional machines, are also possible,provided that all types of players can detect the differences betweenspecies (1) to (5). As described above, low-cost players, which areideal for home or portable use, have small memories and low processingspeeds. Professional machines, however, may be used as network servers,have extremely large memories and high processing speeds.

Here, there may be differences between players as to the titles forwhich emulated AV functions may be used. While low-cost players may onlyperform AV functions for species (1), professional players may performemulated AV functions for species (1), (4), and (5).

In the above case, the title search pointer table is composed as shownin FIG. 23. This table includes a first flag showing whether there isonly one set of route information, a second flag showing whether thereis any loop information, a third flag showing whether there is anyautomatic branch information, and a fourth flag showing whether there isany interactive branch information. Here, species (1)-(6) can beidentified by using these flags to detect the presence of loopinformation, automatic branches, and interactive branches. Titleplayback types are originally formed in this way, although in thepresent embodiment the “sequential single PGC identification” flag showswhether there is only one set of route information, and the other flagsshow whether there is any loop information, so that the title playbacktypes are expressed in a format suited to AV devices.

It is also possible for a flag showing the presence of a certain kind ofcommand (such as commands related to control of a timer) to be providedin the title playback table. The presence of commands which relate tocontrol of a timer makes special kinds of time control possible for thetitle in question. Such control, however, make a display of reproductiontime inappropriate, so that a flag showing its presence needs to beprovided.

The permitted function determination table should not be construed asbeing limited to a determination of whether a function is possible baseon a combination of the functional and structural characteristics of theroute information of the title. For example, when a multi-PGC flag and a“no branch” flag are provided, the determination of whether execution ispermitted for the time search function and the reproduction time displayfunction can be made when these flags are “On”, with the functions beingallowed for routes which are made up of a plurality of PGCs but whichare sequential with no branches.

The present embodiment also describes the case where the condition forthe setting of the automatic branch flag at “On” is the presence of abranch command for an automatically-performed branch in the PGC commandfield forming the title, although it may also be set when anautomatically executed command is present in a PGC. As one example, adefault execution for when there is no user interaction can be set as abutton attribute in the Highlight information stored in a VOB, so thatthe presence of buttons which have default execution attributes can beused as the condition that branch instructions are present.

In the present embodiment, the condition for the setting of the “nobranch between PGCs” flag at “On” was described as being a complete lackof branch information between titles, although if instructions forbuttons which are executed due to user interaction are present, thisflag may still be set at “On”. In this case, titles which include manualbranches to other titles will still have the “no branch between PGCs”flag set at “On”, so that if the “sequential single PGC identification”flag is “On”, the title programming function may still be performed forthis title. However, once such a manual branch is performed duringreproduction, this will result in the reproduction order in the schedulelist no longer being valid, so that the reproduction apparatus needs toperform the invalidation of the remaining title programs in the schedulelist.

The following is another example of the stored content of a multi-titledisc. In this example, five episodes of a popular drama series arestored on the disc, as video titles (1) to (5), with a multi-storyinteractive title which uses the video information of titles (1) to (5)being stored as video title (6). In this case, image titles (1) to (5)are all sequential single PGC types, so that successive reproduction of(1) to (5) is possible using the title programming function. In thiscase, the “no branch between titles” flag in the VM internal titlesearch pointer table area is “Off”, so that these titles can bereproduced successively in order.

The VOB position information table of the present invention has beendescribed as a list of storage locations for VOBs, based on which thedisc reproduction apparatus reads VOBs, although by storing partialareas of the storage locations of the VOBs in this table, the opticalpickup can be made to read only part of the VOBs, such partial readingbeing known as “trimming”. These trimmed parts of VOBs are indicated inunits called cells. By doing so, by indicating partial areas in the VOBposition information, only part of a VOB is used as a core part, so thatthe efficiency with which video materials are used can be increased.

In the present embodiment, a VOB unit consists of one GOP. It isneedless to say that if the stored video information has a reproductiontime of about a second, a VOB unit may consist of two or three GOPs witha very short reproduction time. In this case, a management informationpack is set before such a plurality of consecutive GOPs. The managementinformation pack is then effective for such plurality of GOPs.

In the present embodiment, digital moving picture data according toMPEG2 standard is used for the moving picture data. However, other kindsof moving picture data, such as the digital moving picture data underMPEG1 or digital moving picture data with a conversion algorithm otherthan DCT (Discrete Cosine Transform) under MPEG, may be used so long asthe moving picture data can be combined with audio data and sub-picturedata to form multimedia data.

In the present embodiment, management information packs are included inVOBUs in units of GOPs, these being the units of reproducing movingpicture data. However, it should be obvious that if the method forcompressing digital moving pictures changes, the unit of the managementinformation pack changes according to the compression method.

Finally, a method for producing the optical disc used in the presentembodiment is described. The editor prepares master tapes, such as videotapes of various shots filmed with video cameras and music tapes inwhich songs and sounds are recorded live. The moving pictures and soundsin the tapes are digitized and loaded into a nonlinear editing machine.The editor creates menus and items using application programs, such as agraphic editor provided in an editing machine, and reproduces video andsounds frame by frame. The editor also creates management informationpacks including Highlight commands using a GUI generator and the like.The editor then encodes the above data under MPEG to create video data,audio data, sub-picture data, and management information packs. Afterthis, the editor creates VOB units and VOBs using the nonlinear editingmachine. The editor also assigns numbers to the VOBs. Also, the editorcreates PGC information #1, #2, #3, . . . , #n, a VM title searchpointer table, and a video manager. The editor then loads these sets ofdata into the memory of a workstation.

The data is converted into logical data sequences so that the data isrecorded in the file area. The logical data sequences are recorded ontoa medium, such as the magnetic tape, then converted to physical datasequences. The physical data sequences include volume data with ECC(Error Check Code), Eight-to-Sixteen conversion, and data in the lead-inarea and lead-out area. A master optical disc is produced using thephysical data sequences. Then, copies of the master optical disc aremanufactured by using a pressing machine.

Conventional CD manufacturing machines may be used for manufacturing theabove-constructed optical disc with the exception of the processesrelated to the generation of logical data sequences for the dataconstruction of the present invention. These manufacturing methods aredescribed in Heitaro Nakajima and Hiroji Ogawa: “Compact Disc Dokuhon”,Ohmu Ltd. and Applied Physics Society Optics Meeting: Optical DiscSystem, Asakura Shoten.

Commercial Applications

The multimedia optical disc of the present invention can be used forstoring both sequential video titles and interactive video titles, andso allows the distribution and retailing of optical titles which on amulti-title disc.

The reproduction apparatus and method of the present invention allow thereproduction of the above disc by household AV equipment with limitedmemory capacity.

Although the present invention has been fully described by way ofexamples with reference to the accompanying drawings, it is to be notedthat various changes and modifications will be apparent to those skilledin the art. Therefore, unless such changes and modifications depart fromthe scope of the present invention, they should be construed as beingincluded therein.

1-28. (canceled)
 29. A recording medium having video data to be read and reproduced by an audio-visual device in accordance with a reproductive order indicated by route information, the recording medium comprising: a plurality of pieces of video information; route information, to be read by said audio-visual device, defining a reproduction route by specifying at least one reproductive order of the plurality of pieces of video information; and management information for managing the plurality of pieces of video information whose reproductive order is specified by the route information, wherein the management information indicates whether or not to permit access to the plurality of pieces of video information, independently from the reproductive order thereof.
 30. A reproduction apparatus for the recording medium of claim
 29. 